Patients who had a history of allergies to midazolam and/or dexmedetomidine; delirium, developmental delay, or mental retardation, as reported by parents; an American Society of Anesthesiologists classification greater than III; any known previous reactions to anesthesia; or a history of asthma or an anticipated difficult airway and concomitant disease (neuromuscular scoliosis or neurodegenerative disease) were excluded from the study.